The invention relates to apparatus for subdividing running webs of paper, cardboard, textile material, metallic foil, plastic foil or the like. More particularly, the invention relates to improvements in apparatus which are designed to sever and simultaneously remove from running webs fragments which develop as a result of severing.
It is well known to position pneumatic dust- or fiber-expelling devices adjacent the slot which is formed by one or more rotary disc-shaped or otherwise configurated knives serving to sever the running web in the direction of its advancement toward a cross cutter or to another destination. The pneumatic devices serve to relieve the sections of a severed web of particles of web material which adhere to the sections, particularly in the region of the slot between the sections, and which also tend to adhere to the knife or knives as well as to other parts which contact the severed web. In addition, fragments of a severed web are likely to float in and contaminate the surrounding atmosphere and to ultimately gather on the floor, on the machine frame or elsewhere in the plant. Heretofore known pneumatic dust removing and collecting devices are not entirely satisfactory because a substantial percentage of fragments continues to adhere to the severed web and/or to the knife or knives and/or to the machine frame. This necessitates frequent thorough time-consuming and expensive cleaning of the knives, of the machine frame and/or of any other parts which gather fragments of severed web material. Each cleaning necessitates a prolonged stoppage of the machine with attendant losses in output, especially if the machine constitutes one unit of an entire production line, e.g., a line which serves to convert wide and very long webs into exercise pads, steno pads or other stationery products. The same holds true when a wide and long web is to be converted into stacks of paper sheets, cardboard sheets or like commodities.
It has been found that longitudinal cutters (i.e., apparatus which sever a running web longitudinally in the direction of advancement of the web) are particularly likely to generate substantial amounts of dust.